I've kept one of these off and on since my early 20's. There are many options that can be used for the base book. The one above reminds me of my third one in which I put the pages I wanted to keep into a plastic sleeve and put it in a binder. I still have it around here somewhere, if I can find it in a timely manner I will share some page images on my Instagram.
The one I'm doing now is just a folder in my documents folder on my computer in which I put quotes, images and info pages that catch my interest. When I get stuck I will open the folder and look through the accumulated material and eventually something will get me thinking and then creating. It has helped me out of a number of creative blocks.
You can do it too and maybe you will find it as interesting as I do and as useful. Below are a few of the pages from my current collection hope you find them interesting.